Apparatus for the heating or annealing of materials in elongated form

ABSTRACT

An apparatus for the heating of aluminum wire and other elongated materials by electrical resistance heating comprises two electrolyte containers within which are positioned cylindrical electrodes and a suitable electrolyte with the material to be treated drawn through the containers along the longitudinal axis of the electrodes. A guide path for the elongated material includes a driven guide roller such that the elongated material leaving the first container and entering the second container proceeds along a substantially vertical or inclined path. Each of the electrolyte containers are provided with an overflow means to retain, purify and recirculate the electrolyte. The driven guide roller is surrounded with an annular trap structure for catching any liquid flung from the material passing over the roller.

Zettl et al.

[ Dec. 16, 1975 APPARATUS FOR THE HEATING OR ANNEALING OF MATERIALS IN ELONGATED FORM Inventors; Heinrich Zettl, Lohnberg; Klaus Decker, Rehe, both of Germany Assignee: Firma Henrich KG, l-lorbach,

Germany Filed: Nov. 4, 1974 Appl. No.: 520,750

Foreign ApplicationPriority Data Nov. 9, 1973 Germany 2356003 US. Cl. 219/155 Int. Cl. C21D 9/62 Field of Search 219/1'55 References Cited UNITED STATES PATENTS Primary ExaminerJ. V. Truhe Assistant ExaminerD. A. Tone v v r Attorney, Agent, or Firm-Edmund M. Jaskiewicz [5 7] ABSTRACT An apparatus for the heating of aluminum wire and other elongated materials by electrical resistance heating comprises two electrolyte containers within which are positioned cylindrical electrodes and a suitable electrolyte with the material to be treated drawn through the containers along the longitudinal axis of the electrodes. A guide path for the elongated material includes a driven guide roller such that the elongated material leaving the first container and entering the second container proceeds along a substantially vertical or inclined path. Each of the electrolyte containers are provided with an overflow means to retain, purify and recirculate the electrolyte. The driven guide roller is surrounded with an annular trap structure for catching any liquid flung from the material passing over the roller.

29 Claims, 7 Drawing Figures US. Patent Dec. 16, 1975 Sheet 1 of3 3,927,296

l'l i'Hl' Sheet 2 of 3 3,927,296

U.S. Patent Dec. 16,1975 Sheet3of3 3,927,296

l Un APPARATUS FOR THE HEATING OR ANNEALING OF MATERIALS IN ELONGATED FORM The present invention relates to an apparatus for heating and/or annealing materials in elongated form, such as wires, strands of wires, cables, rods, tapes and the like and particularly aluminum wire, more particularly, to such an apparatus in which the elongated material is subjected to resistance heating and the electrical current is fed to the wire by means of electrolytes in containers through which the material is passed.

Aluminum wire is being increasingly used in place of copper wire for many industrial and commercial applications. When aluminum wire is drawn down in a wire drawing machine a considerable quantity of a deposit remains on the drawn wire which consists mainly of lubricant residue and abraded material. Because of the inherent property of aluminum wire to oxidize, the surface of the aluminum wire is covered with a very tough oxide film of high electrical resistivity. These deposits and oxide layers are characteristically unevenly distributed over' the surface of the wire.

In a conventional apparatus for annealing by resistance heating, electrical current is supplied to the wire by means of contact rollers. The current supply arrangement is not feasible with aluminum wire because the deposits and residues on the wire accummulate on the running surfaces of the contact rollers and eventually disrupt the flow of current because of the non-conductive properties of such residues.

vA preliminarycleaning of the wire by chemical, mechanical or other means is not practical since the high operating speeds of such wire processing machinery precludes any provision for the time required for such a cleaning operation.

Various measures have been proposed to remove continuously these deposits from the running surfaces of the contact rollers during the process but have not been satisfactory because of sparking. This sparking or electrical discharge is caused by the fluctuating transfer resistance between the wire and the contact rollers caused by the impurities and oxide layers adhering to the wire surface. This sparking damages the'surface of the wire and the resulting erosion produces a pitting on the surface of the contact rollers which renders them unusable after a relatively short time.

Accordingly, proposals have been made to supply electric current to the wire by means of electrodes when subjecting such a wire to resistance heating. Such an arrangement precludes sparking. However, the disadvantage with such an apparatus has been noted that the current supply and the annealing temperature cannot be maintained at a relatively constant level. This is particularly noticeable when annealing aluminum wire because of its high coefficient of expansion wherein smaller temperature fluctuations in the annealing zone lead to considerable differences in the elongation of the wire. As a result, non-uniform and uncontrollable annealing results are obtained which are manifested by differences in the tensile strength, elongation and elec trical conductivity of the annealed wire.

In such apparatus, running of the wire horizontally permitted electrolyte to leak out onto the wire at those points where the wire or elongated material entered or left the containers. The results were uncontrollably inaccurate readings of the length of the annealing path. Such inaccurate readings were particularly noted when oscillations were set up in the wire. The oscillating wire was thus subjected to a varying current from the electrolyte as it passed through the containers. There was also the risk of sludge and other deposits forming around the inlet and outlet apertures of the electrolyte containers during operations. This also produced large variations in the quantity of electrolyte removed and the distance it was carried thus introducing an additional factor which caused an uncontrollable variation in the length of the annealing path. It was not possible to solve this problem by installing seals at the inlet and outlet apertures of the containers for the wire. For such a seal to be effective the frictional force at these points would be so great that wire of low tensile strength, such as aluminum wire would be stretched and depending upon the friction the surface would be damaged. Further, such sealing means are subject to very considerable wear particularly at the high speeds at which the wires are passed through the apparatus and when using electrolytes which are highly reactive. The result is high maintenance costs and poor reliability in operation.

It was also found that the electrolyte adhering to the wire exerted a considerable influence in maintaining the annealing temperature at a constant value. During heating of the wire the adhering electrolyte must be evaporated. Apart from the fact that additional heat energy was required this also caused the wire temperature to fluctuate considerably particularly when the quantity of electrolyte adhering to the wire varied. This always occurred since the quantity of electrolyte carried along out of the electrolyte container varied according to oscillations in the wire, differences in the surface structure of the wire and other factors as discussed above.

It is further pointed out that because of the evaporation of the electrolyte residues thereof were baked onto the surface of the wire. As a result there was a nonuniform transfer of current inthe second electrolyte bath which produced irregular annealing temperatures.

It is therefore the principal object of the present invention to provide a novel and improved apparatus for the heating of aluminum wires and other elongated materials by electrical resistance heating using an electrolyte.

It is another object of the present invention to provide such an apparatus wherein the current supply and thus the annealing temperature of the wire is readily maintained at a constant level for long and reliable operation.

The present invention essentially comprises an apparatus for heating and/or annealing elongated materials, such as wire, standed wire, cables, rods, tapes or the like and preferably aluminum wire by resistance heating. The apparatus comprises a first and a second electrolyte container through each of which the elongated material is passed. Electrode means are provided in each container to form an electrical connection with the elongated material passing through the container by means of the electrolyte. The path of the elongated material leaving the first container and the path of the elongated material entering the second container is inclined and preferably substantially vertical. There are overflow means for each container.

The apparatus according to the present invention has the advantage of providing an accurately located liquid level in both containers so as to define between them a precise path for heating or annealing of the wire or other elongated material. The result is a precisely defined and constant annealing path length between the containers contrary to the containers in known apparatus in which the wire is run horizontally and as a result the electrolyte flows out onto the wire on the annealing path at those points where the wire enters and leaves the containers.

The present invention provides that the electrolyte runs back by gravity into the first electrolyte containers in a direction opposite to that of the movement of the wire leaving the electrolyte container. As a result very little electrolyte adheres to the wire which produces a saving in the heat energy required.

In order to avoid temperture fluctuations in the wire produced largely by the adherence of the electrolyte to the wire the liquid electrolyte adhering to the wire is removed before the wire reaches the second electrolyte container. The present invention provides that the following arrangements can be utilized either singly or together to avoid such temperature fluctuations:

l. A stripping device is positioned downstream of the first electrolyte bath of a heating zone or path.

2. A blowing nozzle is provided downstream of the first electrolyte bath of a heating zone or path.

3. A wire guiding or deflecting roller with a trap is positioned downstream of the first electrolyte bath of a heating zone or path. Liquid is flung off the wire because of the centri-fugal effect as the wire passes over the deflecting roller and this liquid is collected in a channel of the trap surrounding the roller.

The present invention also provides for the maintenance of the supply of current at a constant level and thus maintaining the annealing temperature of the wire uniform by the following measures:

1. Purification of the electrolyte to maintain the conductivity at a constant value.

2. Maintaining the electrolyte temperature constant so as to maintain the conductivity at a constant value.

3. Continuous or periodic measurement of the conductivity of the electrolyte in order to initiate counter measures should the conductivity deviate from an established value.

4. Requlation of the electric current to maintain constant the supply of current to the wire in the event of any changes of conductivity of the electrolyte and/or the wire.

Items one and two can be incorporated within a closed circuit within which the electrolyte circulates. The items one-four may each be carried out individually or in any desired combination nation thereof. In addition to regulation of the electric current, it may also be desirable to provide for electrical requlation of the voltage in order to compensate for any voltage fluctuations and any temperature variations resulting therefrom. Provision may also be made for the regulation of the electric energy or regulation of the temperature of the wire or elongated material to be heated or annealed.

Other objects and advantages of the present invention will be apparent from the accompanying description when taken in conjunction with the following drawings, which are exemplary, wherein;

FIG. 1 is an elevational view, partially in vertical section, of an apparatus according to the present invention;

FIG. 2 is a sectional view of a modified electrolyte container according to the present invention;

FIG. 3 is a sectional view taken along the line III-III of FIG. 3;

FIG. 4 is a sectional view taken along the line IV-IV of FIG. 1;

FIG. 5 is a sectional view of an electrolyte container of FIG. 1 and showing a modification thereof;

FIG. 6 is a view similar to that of FIG. 5 and showing a further modification; and

FIG. 7 is a vertical sectional view of a further modification of a portion of the apparatus of FIG. 1.

Proceeding next to the drawings wherein like reference symbols indicate the same parts through the various views a specific embodiment anad modifications of the present invention will be described in detail.

The elongated material which is to be heated in this described embodiment comprises a wire 1 supplied from a wire drawing machine which is not shown in the drawings and guided by a roller 2 into the vertical direction to enter an opening 3 in the bottom of an elelctrolyte container 4. The wire 1 passes through the container 4 and its direction is then reversed by a guide roller 5. The wire 1 is then passed through a second electrolyte container 6 and emerges through a bottom opening 7 and is fed from this apparatus over a guide roller 8. The wire 1 may now be supplied to a wire reeling or extruding apparatus as known in the art. The guide rollers 2, 5 and 8 are positively driven in order to minimize the tension on the wire particularly as it passes along the annealing path between the containers 4 and 6.

Reversal of the direction of movement of the wire is generally avoided because the wire is considered to be in a very sensitive condition as it travels along the annealing path. However, when the guide roller 5 changes direction of the wire 1 in the initial portion of the annealing path, preferably immediately following the first contact point, and the roller is driven, such a roller may be advantageous. As the wire 1 passes along the annealing path the temperature of the wire is increased progressively from its original temperature to the maximum temperature which is reached immediately prior to the immersion of the wire in the second bath 6. The presence of the driven guiding roller 5 in the first portion of the annealing path thus has no detrimental effect on the wire since in this region the wire is still relatively insensitive because of its relatively low temperature. On the other hand, the use of the guide roller 5 has the advantage that the wire emerging from the frictional contact with the guide roller 5 enters the critical stage of the annealing path in a completely untensioned condition. In this zone it is thus possible to subject the wire to extremely light mechanical loading only because of the high temperature prevailing in this zone. The effect of all resistances acting upon the wire before it enters the annealing path, such as the frictional resistance encountered in the first bath 4, are neutralized by this roller 5. In the absence of such a driven roller such forces would be applied by means of a drawing off roller, a take-up device or the like mounted in the rear portion of the annealing path at which point the wire is in a very sensitive condition. This could result in the wire being permanently stretched with the detrimental effects associated. therewith such as loss of elongation, decrease in tensile strength, and other similar effects. With the present invention, these disadvantages and drawbacks are avoided. By positively driving the other guide rollers of the apparatus the resistances acting on the wire 1 are neutralized by stages and the tensile stresses in the wire are kept at a low level. This is not only important in the annealing zone but it is also of the greatest importance in the case vof already soft annealed wire in order to prevent undesirable stretching of such wire. The use of positively driven guide rollers and the untensioning of the wire produced thereby is thus a very important feature paraticularly in the case of wires having a relatively low tensile strength and great softness such as aluminum wire.

Such rollers can also be used to remove liquid from the wire by centrifugal force.

The electrolyte containers 4 and 6 are so mounted that their heights can be adjustable by a structure known in the art and not described in detail herein. In a similar manner, guide roller 5 and also the rollers 2 and 8 may also be vertically adjustable in order to vary the length of the annealing path between the containers 4 and 6.

Electrodes 9 are provided in each container as shown in greater detail in container 4 and these electrodes are connected to a suitable source of electrical energy 10.

The electrodes 9 may also be formed so as to constitute containers for the electrolyte.

By means of the adjustability of the heights of the electrolyte containers and guide rollers the apparatus can be readily adjusted to the requirements of different materials, the cross'sectional area of the material to be heated, and other requirements which may be encountered with respect to the particular heating or annealing operationto' b'e preformed." v

A supply of electrolyte 'is constantly fed into the electrolyte container4 through a supply connection 1 1. The electro-lyte may overflow over the upper edge 12 of container 4 and is then connected in an overflow chamber 1 to be subsequently flowed through a pipe 14 to a storage container. The overflow electro-lyte is then and determined by the overflow levels of the containers 4 and 6 since the surfaces 12 of the respective electrolytes are always horizontal and can be readily controlled so that the levels thereof do not fluctuate.

The containers 4 and 6 have acircular cross-section and the electrodes 9 are cylindrical in shape so as to surround the wire 1 passing therethrough. The wire is moved along the longitudinal axis of the electrode 9 so that the wire is always maintained at the same distance from the electrode. As a result a uniform electric current will flow in the electrolyte containers 4 and 6 to the wire 1 passing therethrough.

In the modification of FIG. 2, the wire 1 passes at an upward angle through aelectrolyte container 24 which is similarly in an inclined position. The electrolyte liqstructure of the container 24'may the container 4.

The vertical or inclined mounting of the electrolyte containers has the further advantage that the wire is prevented from sagging in theecontainers. Thus, abrasion of the wire at the inlet and outlet appertures is avoided and more particularly, eachelectrolyte container may be open at its end facing toward the annealing path so that all friction is eliminated-at this point where the wire emerges from or enters into the container. Further, variations in the current transmitted from the electrode to the'wire when'the wire sages caused by differences in the distance between the upper and lower surfaces of the wire and the electrodes is avoided. The electrodes are preferably of a circular cross section with the wire positioned axially within each electrode. Further, the frictional resistance of the wire passing through the electrolyte is reduced as compared to a sagging or drooping wire and thus whipping or other movement of the wire when passing through the electrolyte container is prevented.

The vertical mounting of the electrolyte containers also avoids the possibility of constituents dissolved in the electrolyte from settling or depositing upon the electrodes. Apart from the fact that such deposits on the electrolyte container necessitate repeated cleaning these deposits will cause indesirable variations in current transfer andconsequently variations of the temperature in thewire. The advantages of this vertical arrangement are readily apparent as compared to the horizontal mounting or the containers' as previously carried out in the art. In such horizontal containers the deposits collected in the lower portion of the containers eventually covered the electrodes in this region. The current transfer from the electrode to the wire thus became progressively poorer as the deposits increased. The result was a non-uniform distribution of electric current over the cross-section of the electrolyte bath and consequently of the wire itself.

The vertical mounting of the electrolyte containers prevents the settling of such residues on the electrodes. On'the contrary, according to the present invention the residues are continuously drawn out of the container together with the electrolyte flowing downwardly through the inlet or outletapt-irture. I

It has been found that the vertical "mounting of the electrolyte containers and the wire passing therethrough is preferable. However, an inclined arrangement of the container and the wire is advantageous in that it preventselectrolyte liquid which drains from the lower aperture of the container through which the wire is passed from dripping onto the guide rollers therebelow. i

As can be seen in FIG. 3, an electrolyte container comprises two concentric telescoping mutually rotatable tubular members 30 and 31. 'The tube 31 is constructed as the electrode and each tubular member has a respective longitudinal slot 3 2 a nd 33 in the peripheral wall thereof. In order to insert the wire in an electrolyte container, the tubular members rotated with correspond to that of I respect to each other until their respective slots 32 and uid escaping from inlet opening 23 falls in the direction 33 are in registration. The wire is then inserted and the tubular members 30 and 31 are rotated into 'a position as shown in FIG. 3 to seal the container and to prevent the escape of liquid through the slots.

The electrolyte containers 4 and 6 have frusto-conical shapes at their bottom ends 33*and 34. Any sludge or the like in the electrolyte is thus withdrawn from the container together with. the electrolyte through the openings 3 and 7 and thus no deposits will be formed downstream from the. electrolyte container 4v for the.

purpose of removing electrolyte adhering to the wire. In the rear of the stripper 35 there is a blowing nozzle tion, a pressure spray nozzle can also be provided so that the jet will run concurrently with the wire and terminate in the second contact bath of the'annealing path.

The. electrolyte is discharged from the container 6 at 54to be cooled and again pumped through pipe 53 36 such as shownin FIG. 7 wherein air is forced through the inlet 37.

Any residual particles of electrolyte liquid on the 2 wire are flung off by centrifugal force when the wire,

passes around the guide roller 5. In order to prevent, such liquid dropplets fromreaching the wire in the annealing zone itself, i.e. the zone above the electrolyte. container 6, an annular trap 38 is positioned to surround the roller as shown in FIGS. 1 and The liquid 3 drops. thus are collected in a channel 3 9 in the trap and run downwardly back into the storage vessel through a run-off or drain 40. [n.order to prevent any downflow ing liquid from escaping through the wire inlet and outlet apertures 41 and 42, sleeves 43 and 44 are mounted in these apertures such that the upper ends of the sleeves projecting through the annular trap 38 are above the level of any liquid flowing downwardly through the channel 39. v In order to. facilitate positioning of the wire around theroller 5 theannular collecting ring 38 may be con-.

for removing electrolyte from the wire other than'described above. v v Thefeature of flinging off the liquid centrifugally fron the wire may be employed at other positionsalong the annealing path other than as shown in FIG. 1. The

liquid may also be removed downstream of. the second container v6 or downstream of a subsequent rinsing zoneor at other similar places.

In order to protect the wire 1 from the electrolyte in an atomized, or spray form or.to provide a protective atmosphere around the wire, a

in the annealingipath:

tube 60is positioned between the guide roller 5 and the electrolyte container 6 toenclosethe wire 1.

After the wire has traversed the annealing p ath, it,

the electrolyte, luminescence occurs in the immediate vicinity of the wire on the, surface of the liquid. It has been found that the flow of electric current is very considerably distorted by the luminescence.

In order to inhibit this. luminescence, thereis vided as shown in FIGS an auxiliary tube 5.1 through Y which the wire 1 passes into the containerfi and the end of the tube 51 is immersed in theelectrolyte in the in large quantities at the point of entry of the hot Wire into the electrolyte. By increasing the rateof flow of the electrolyte in this region the electrolyte will be at a. substantially lower temperature than thatof the ,wire entering the container. Thetube 51, in effect. interposes an additionalshort column of electrolyte at the point of entry of the hot wire. into theactual electrolyte bath in the container. As a modification or as an addienters the electrolyte container 6 As the wire enters;

back into the container. Because of the small cross-sectional area of the tube 51 it is possible that occasionally sufficient, electrolyte will not be supplied to the container 6. As shown in FIG. 6, an additional connection 55 is thus provided through which supplemental electrolyte can be pumped into thecontainer 6.

It is also. possible to use a nozzle such as that shown in FIG. 7 instead'of the tube 51. The wire 1 isled into the container axially through the nozzle. An electrolyte is supplied under pressure through the inlet connection 37 to be discharged as a powerful jet from the nozzle aperture 46 and thus penetrate deepy into the electrolyte iriv the container 6. This jet can be constructed so that the intensity of the pressurized stream and thus its output is adjustable.

Acccording to the present invention an electrolyte can be used which also exerts a pickling action upon the wire whereupon residue on the wire is removed and the wire surface'is bright and shiny. Such a bright surface has a favorable effect upon transfer of electric current. If alternating current is used, then depending upon the frequency of the current supply and on the electrolyte used an alternate picklingand/or oxidation of the wire will occur. If a direct current supply used,

then depending .on the electrolyte usedand the polarity in the individual containers the wire is either pickled or anyinterposed cooling device for supplying the container. The electrolyte supplied may be at the same temperature as that of the actual electrolyte bath. within .the container or it may be supplied at a different temperature.

The above described maintenance of the electrolyte temperature may also be utilized to maintain constant its quenching effect on the hot wire or to control or influence the temperature curve or gradient of the wire with respect to the temperature of the electrolyte.

The several features of the invention as described herein may also be used with electrolytes which have a neutral reaction with the surrounding atmosphere.

Means may also be provided for controlling the amount .of electrical energy supplied to the? wire in order to maintain a uniform distribution of the temperature. Thus, it is not, unusual for the conductivity of the electrolyte tochange during the process because of either impurities brought in on the wire and deposited in the electrolyte, by chemical changes (for example,

electrolysis), by changes in concentration (for exam-' ple, by evaporation and active material removed on the wire by temperature changes in the electrolyte and other similar reasons.

It is apparent that theapparatus according to the present invention is particularly suited for heating or annealing of material in elongated form and preferably in conjunction with a preceeding drawing machine, such as a wire drawing machine, and a subsequent extruder and/or a reeler.

It will be understood that this invention is susceptible to modifications in order to adapt it to different usages and conditions, and accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of appended claims.

What is claimed is: i

1. In an apparatus for the heating of aluminum wire and other elongated materials by electrical resistance heating, the combination of first and second electrolyte containers through which the elongated material to be treated is passed, electrode means in each container for making an electrical connection through an electrolyte with the elongated material passing therethrough, means for defining a substantially vertical path for the elongated material through the first and second container, and overflow means on each of said electrolyte containers.

. 2. In an apparatus as claimed in claim 1 and means down-stream of said first container for removing liquid from the elongated material after'emerging from the first container.

3. In an apparatus as claimed in claim 1 wherein said electrode means of each container is cylindrical and the elongated material moves therethrough along the longitudinal axis thereof.

.4. In an apparatus as claimed in claim 1 wherein said path means comprises a driven guide roller between said first and second containers.

5. In an apparatus as claimed in claim 4 and annular trap means around said driven guide roller to catch any liquid flung therefrom.

6. In an apparatus as claimed in claim 5 wherein there are apertures in said trap means for the passage of the elongated material to and from the guide roller, and

drain means in the bottom of said trap means, and

means in said trap means for preventing any trapped liquid from flowing through said apertures.

7. In an apparatus as claimed in claim 6 wherein said flow preventing means comprises a sleeve in each of said apertures, the ends of the sleeveswithin said trap means projecting therein such that said ends are at a higher level than the level of liquid within said trap means.

8. In an apparatus as claimed in claim 4 wherein said driven guide roller is disposed downstream of said first container and adjacent thereto and positioned in the initial portion of the path of the elongated material between said containers.

9. In an apparatus as claimed in claim 4 and means for adjusting the height of at least one of said containers or said guide roller.

10. In an apparatus as claimed in claim 1 wherein each of said containers comprises-a pair of concentric telescoping rotatable tubular members and each mem- 13. In an apparatus as claimed in claim 1 and measuring and controlling means for maintaining constant the temperature gradient of the elongated material along said path.

14. In an apparatus as claimed in claim 1 and measuring and controlling means for maintaining constant the temperature of the electrolyte.

15. In an apparatus as claimed in claim 1 and means for measuring the conductivity of the electrolyte, and means for regulating the electrical energy supplied to the elongated material between the first and second containers.

16. In an apparatus as claimed in claim 1 wherein said containers each contain an electrolyte of a high electrical conductivity.

17. In an apparatus as claimed in claim 1 and means including purifying means for recirculating the electrolyte.

18. In an apparatus as claimed in claim 1 and means for pickling the elongated material in said containers.

19. In an apparatus as claimed in claim 1 and means for supplying alternating current to the electrodes to heat the elongated material passing therethrough.

20. In an apparatus as claimed in claim 1 and means for supplying direct current to the electrodes to heat the elongated material passing therethrough, and switch means for controlling the pickling so that the electrolyte will produce a bright pickling of the elongated material.

21. In an apparatus as claimed in claim 1 wherein said first and second containers each contain different electrolytes.

22. In an apparatus as claimed in claim 1 and a tubular member enclosing the elongated material along that portion of the path leading tosaid second container.

23. In an apparatus as claimed in claim 1 and means for establishing a protective atmosphere surrounding the elongated material between said first and second containers. y

24. In an apparatus as claimed in claim 1 wherein the electrolyte within said containers is such as to have a neutral reaction with the surrounding atmosphere.

25. In an apparatus as claimed in claim 1 and means before the second container for containing an electrolyte but no electrode through which the elongated jfma terial is passed. 3'

26. In an apparatus as claimed in claim 25 wherein said electrolyte containing means comprises a tube of a relatively small cross-sectional area extending into said second container and continuously supplied with electrolyte.

27. In an apparatus as claimed in claim 25 and nozzle means with said electrolyte containing means for injecting electrolyte in the direction of movement of the elongated material toward its entry point into said second container.

28. In an apparatus as claimed in claim 25 and means in said electrolyte containing means for one of cooling the electrolyte therein or for increasing the rate of circulation of the electrolyte therethrough.

29. In an apparatus as claimed in claim 1 and a drawing apparatus for feeding elongated material to said first electrolyte container, and means receiving elongated material from said second container for one of extruding or reeling the elongated material. 

1. In an apparatus for the heating of aluminum wire and other elongated materials by electrical resistance heating, the combination of first and second electrolyte containers through which the elongated material to be treated is passed, electrode means in each container for making an electrical connection through an electrolyte with the elongated material passing therethrough, means for defining a substantially vertical path for the elongated material through the first and second container, and overflow means on each of said electrolyte containers.
 2. In an apparatus as claimed in claim 1 and means down-stream of said first container for removing liquid from the elongated material after emerging from the first container.
 3. In an apparatus as claimed in claim 1 wherein said electrode means of each container is cylindrical and the elongated material moves therethrough along the longitudinal axis thereof.
 4. In an apparatus as claimed in claim 1 wherein said path means comprises a driven guide roller between said first and second containers.
 5. In an apparatus as claimed in claim 4 and annular trap means around said driven guide roller to catch any liquid flung therefrom.
 6. In an apparatus as claimed in claim 5 wherein there are apertures in said trap means for the passage of the elongated material to and from the guide roller, and drain means in the bottom of said trap means, and means in said trap means for preventing any trapped liquid from flowing through said apertures.
 7. In an apparatus as claimed in claim 6 wherein said flow preventing means comprises a sleeve in each of said apertures, the ends of the sleeves within said trap means projecting therein such that said ends are at a higher level than the level of liquid within said trap means.
 8. In an apparatus as claimed in claim 4 wherein said driven guide roller is disposed downstream of said first container and adjacent thereto and positioned in the initial portion of the path of the elongated material between said containers.
 9. In an apparatus as claimed in claim 4 and means for adjusting the height of at least one of said containers or said guide roller.
 10. In an apparatus as claimed in claim 1 wherein each of said containers comprises a pair of concentric telescoping rotatable tubular members and each member having a longitudinal slot in the peripheral wall thereof.
 11. In an apparatus as claimed in claim 1 wherein each of said containers has a frusto-conical base.
 12. In an apparatus as claimed in claim 1 and measuring and controlling means for maintaining constant the electric current supplied to the elongated material.
 13. In an apparatus as claimed in claim 1 and measuring and controlling means for maintaining constant the temperature gradient of the elongated material along said path.
 14. In an apparatus as claimed in claim 1 and measuring and controlling means for maintaining constant the temperature of the electrolyte.
 15. In an apparatus as claimed in claim 1 and means for measuring the conductivity of the electrolyte, and means for regulating the electrical energy supplied to the elongated material between the first and second containers.
 16. In an apparatus as claimed in claim 1 wherein said containers each contain an electrolyte of a high electrical conductivity.
 17. In an apparatus as claimed in claim 1 and means including purifying means for recirculating the electrolyte.
 18. In an apparatus as claimed in claim 1 and means for pickling the elongated material in said containers.
 19. In an apparatus as claimed in claim 1 and means for supplying alternating current to the electrodes to heat the elongated material passing therethrough.
 20. In an apparatus as claimed in claim 1 and means for supplying direct current to the electrodes to heat the elongated material passing therethrough, and switch means for controlling the pickling so that the electrolyte will produce a bright pickling of the elongated material.
 21. In an apparatus as claimed in claim 1 wherein said first and second containers each contain different electrolytes.
 22. In an apparatus as claimed in claim 1 and a tubular member enclosing the elongated material along that portion of the path leading to said second container.
 23. In an apparatus as claimed in claim 1 and means for establishing a protective atmosphere surrounding the elongated material between said first and second containers.
 24. In an apparatus as claimed in claim 1 wherein the electrolyte within said containers is such as to have a neutral reaction with the surrounding atmosphere.
 25. In an apparatus as claimed in claim 1 and means before the second container for containing an electrolyte but no electrode through which the elongated material is passed.
 26. In an apparatus as claimed in claim 25 wherein said electrolyte containing means comprises a tube of a relatively small cross-sectional area extending into said second container and continuously supplied with electrolyte.
 27. In an apparatus as claimed in claim 25 and nozzle means with said electrolyte containing means for injecting electrolyte in the direction of movement of the elongated material toward its entry point into said second container.
 28. In an apparatus as claimed in claim 25 and means in said electrolyte containing means for one of cooling the electrolyte therein or for increasing the rate of circulation of the electrolyte therethrough.
 29. In an apparatus as claimed in claim 1 and a drawing apparatus for feeding elongated material to said first electrolyte container, and means receiving elongated material from said second container for one of extruding or reeling the elongated material. 